The present invention relates to a process and apparatus for the treatment of organic emulsions including the separation by coalescence of the dispersed phase from the dispersion phase of the emulsion. The present invention is applicable particularly to such separation involving oily emulsions such as oil-field water, condensates occurring during operation in the petroleum industry, and to emulsions used in various mining industries for the treatment of ore, for example copper or uranium ore. It will be apparent from the following discussion however, that the process and apparatus of the present invention are applicable to the separation of a wide variety of organic emulsions.
Various processes are known for separating oil emulsions by coalescence. Such known processes include percolating an emulsion vertically from above or below, or horizontally, through an organic or inorganic granular material. During such percolation, oily droplets of the dispersed phase of the emulsion are formed on the granular material, and the size of these droplets are increased by coalescence, whereafter the coalesced droplets are separated from the dispersion phase, normally water, through a continuous exhaust operation or through sedimentation.
However, the granular coalescence material gradually becomes clogged due to retention of matter in suspension which is always present to a certain degree in the emulsion to be treated. It thus becomes necessary to remove the coalescence material and to either destroy or clean it outside the apparatus. This is of course a complex and costly operation.
To overcome these disadvantages, it has been attempted to wash the coalescence material while remaining in the apparatus. Such processes have however normally involved the injection of a washing liquid in a direction countercurrent to the direction of normal operation of the apparatus. Such processes have not however resulted in a thorough and complete washing of the coalescence material, particularly when the matter in suspension is present therein in large quantities.
Additionally, various other improvements have been attempted in known processes of separating organic emulsions by coalescence. For example, it has been attempted to add an "oleophilizing" organic compound to the coalescence material in an attempt to increase its capacity for retaining or attracting the oily dispersed phase of the emulsion. Such compounds are normally based on various types of hydrocarbons or amines. Further improvements have involved the addition to the emulsion to be treated of cationic polyelectrolytes of high molecular weight.
All of the above known processes, however, are still associated with certain operational disadvantages.